I went back today for take a photo and as the gates of the garden happened to be open I went to take a look at the other side of the wall. I was astonished to find several very large sandstone stones; they must have been on the land when the house was being built because I cannot imagine they would have been moved very far. (Interestingly the house has the same street number as my own).
The other side of the wall, inside a garden
Both the above and below stones are of a similar shape to the one on the green opposite the house
Another lozenge shaped stone forming a garden wall.
I have featured this stone before, it stands at the top of Grosvenor Road. At first I thought it was sarsen but on closer inspection can see it is sandstone. I cannot help wondering about its history. 
